Balloon occlusion devices are commonly deployed within a vessel during various cardiovascular surgeries to provide isolation of blood flow. During conventional or minimally invasive surgeries, including coronary artery bypass grafting, heart valve repair or replacement, septal defect repair, pulmonary thrombectomy, atherectomy, aneurysm repair, aortic dissection repair and correction of congenital defects, for example, circulatory isolation of the coronary blood flow from the peripheral vascular system is often required to establish cardiopulmonary bypass. Instead of using the traditional methods of aortic clamping, a balloon occluder is sometimes used to isolate blood flow in the aorta. Presently, balloon occluders are built to expand to the approximate lumenal diameter of the vessel, i.e., a balloon occluder with a smaller diameter would be used for the carotid artery while larger balloons are used in the aorta. Balloon occlusion devices are also used in other nonvascular procedures, such as dilation of an esophageal stricture in patients with achalasia, or dilation of an intra and/or extrahepatic bile duct in patients with biliary stenosis.
There are several disadvantages associated with the current methods of inflating a balloon occluder in a vessel or body cavity. First, the optimal size of the balloon occluder for occluding the lumen of the vessel or the body cavity is unknown and is usually estimated according to the average lumenal diameter. The vessel may be affected by atherosclerosis, and the actual lumenal diameter may be reduced. Second, as the balloon is inflated to occlude the lumen of the vessel or body cavity, the point of contact of the perimeter of the balloon with the wall of the vessel or body cavity is uncertain. The operator can only estimate an acceptable level of wall distention. Third, the pressure generated by the expanded balloon on the wall of the vessel or body cavity is unknown. Complications due to over-inflation of the balloon may occur, including (1) atherosclerotic plaque rupture leading to distal embolization, (2) dissection of the vessel wall, (3) pseudoaneurysm formation due to subintimal hemorrhage, (4) aneurysm formation due to hyperextension and weakening of the vessel wall, (5) diverticulum formation due to weakening of the body tissue, and (6) vessel wall rupture or organ perforation.
New devices and methods are thus needed for balloon occlusion of a vessel or body cavity, in order to provide information on the effective diameter of the vessel or body cavity and allow an operator to optimally control the inflation of the balloon without damage to the vessel wall or body tissue.